Blade of Vanos

You have sworn yourself to Vanos, god of wind and storms. In return, he grants you the faintest sliver of his fury.

Once per long rest, you can invoke Judgment of the Storm:

As a special action, you channel the fury of Vanos into your next strike for the next 10 minutes:
The next time you hit with a weapon attack, it deals an extra 1d6 lightning damage, and the target must succeed on a Constitution saving throw (DC = 8 + your proficiency bonus + your Strength modifier) or be stunned until the end of their next turn.

Visual Flare: Your weapon glows with pale blue light, and the faint sound of rolling thunder echoes around you. When you strike, lightning forks out toward the sky—or the ceiling, if indoors.